If you would like to get the sharpest results from your Lumi Ink, you should read this first. After some playing around with Lumi Ink, I have compiled a list of the most important steps one should take to get the best results. In this example, I printed a negative with my inkjet printer which included text. In order for the text to develop clearly, I found it necessary to use the following techniques.
First, you will need:
1 glass pane
1 roll of Scotch tape
1 sturdy surface, such as particle board
& of course, your Lumi Inkodye Kit
Step 1: Don't Use Cardboard, Straight Pins or Thumb Tacks
When cardboard absorbs moisture from the Lumi Ink, which it will, it begins to warp. Pins and thumb tacks also begin to lift away from the underlying surface no matter how secure you think they are. I switched to using a solid work surface and tape and the results were much better. This picture is an example of what happens when cardboard warps and the pressure causes the pins to also come loose. Blurry lines, yuk!
Step 2: Don't Handle Your Negatives
Don't handle your negatives unless you absolutely have to. If you are using the inkjet printer negatives supplied with your Lumi Inkodye Kit, you will notice they are extremely delicate once printed. Every time you touch your negatives, or even look at them wrong, they will get scratched. Before beginning the exposure process, plan out your actions to minimize the number of times you have to move the negative. It's a good idea to clean your negatives in between uses to remove excess ink but don't try to wipe them with anything. If you do, the ink will come off. In other words, handle them as little as possible.
Step 3: Use Glass
You want to get your negative as flat and close as possible to your fabric. Any ripples, waves or space in between the two will translate to loss of definition and blurry lines. Also, you want your negative as secure as possible. If it shifts or blows away completely, your image will be ruined. Using a piece of glass ensures a uniformly flat and secure surface that will not blow away. I used tape on one side of my glass platen so that I could lift and lower it evenly and prevent it from shifting while I moved the piece into the sunlight.
Step 4: Don't Over-Expose
On a typical sunny day with no clouds in the sky, you really don't need to develop your piece for more than five minutes in direct sunlight. It was 2 PM and 80 F when I ran my exposure test. My ink began to noticeably develop within one minute in the sun. On an overcast or cold day, your mileage may vary. As you can see in this picture, there is some difference between the 5-minute and 25-minute exposures but not much. Lumi suggests an exposure time of 10-20 minutes. This might be the best range for most users but on a sunny day, developing in direct sunlight, it's really unnecessary and could cause over-exposure if your negative is not perfectly flat against your piece and has very good light-blocking in the dark areas.
Step 5: Start Small
I'll leave you with one more tip: Always blot away excess dye with a paper towel or absorbent material. Once you place your piece under the glass that I mentioned before, you don't want all that excess to smear and ruin your design.
I'm very glad that I decided to create this Instructable. If I had started on a large piece, a t-shirt perhaps, I probably would have ruined a perfectly good t-shirt. The Lumi kits come with small fabric swatches for a reason. Use them. Remember, everything makes sense in writing but when it comes time to actually do it, it's a lot different. I'm sure you would rather mess up ten small pieces of scratch fabric than a nice piece of white cotton and the only way to do this well is to develop your technique by practicing.
I hope this helps you when you decide to replicate your design onto fabric; learn from my mistakes!
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